EM120 not correctly booting up, unknown wwan control port exposed?

[Loic Poulain]

Hi Aleksander,

On Sun, 23 May 2021 at 00:17, Aleksander Morgado
<aleksander at aleksander.es> wrote:
>
> Hey again,
>
> The "wwan0" thing is unrelated to the actual problem I saw with the
> EM120 going away.
>
> > There is one interesting thing in the MM log, though, maybe it's MM
> > the one causing the issue.
> > See this list of ports and the details for each port reported via udev/sysfs.
> >
> > The first port we find is the net port as we scan net subsystem first:
> >
> > ModemManager[2490]: <debug> [1621709598.546715] [mhi_mbim0] port
> > contents loaded:
> > ModemManager[2490]: <debug> [1621709598.546823] [mhi_mbim0]   bus: pci
> > ModemManager[2490]: <debug> [1621709598.546974] [mhi_mbim0]   device:
> > /sys/devices/pci0000:00/0000:00:1b.0/0000:01:00.0
> > ModemManager[2490]: <debug> [1621709598.547071] [mhi_mbim0]   driver: mhi_net
> > ModemManager[2490]: <debug> [1621709598.547175] [mhi_mbim0]   vendor: 1eac
> > ModemManager[2490]: <debug> [1621709598.547275] [mhi_mbim0]   product: 1001
> > ModemManager[2490]: <debug> [1621709598.547375] [base-manager] adding
> > port mhi_mbim0 at sysfs path:
> > /sys/devices/pci0000:00/0000:00:1b.0/0000:01:00.0/mhi0/mhi0_IP_HW0_MBIM/net/mhi_mbim0
> > ModemManager[2490]: <debug> [1621709598.548559] [filter]
> > (net/mhi_mbim0) port allowed: net device
> > ModemManager[2490]: <debug> [1621709598.548785] [base-manager] port
> > mhi_mbim0 is first in device
> > /sys/devices/pci0000:00/0000:00:1b.0/0000:01:00.0
> > ModemManager[2490]: <debug> [1621709598.549024] [plugin-manager] task
> > 4: new support task for device:
> > /sys/devices/pci0000:00/0000:00:1b.0/0000:01:00.0
> > ModemManager[2490]: <debug> [1621709598.549359] [plugin-manager] task
> > 4: port grabbed: mhi_mbim0
> > ModemManager[2490]: <debug> [1621709598.549489] [plugin-manager] task
> > 4,mhi_mbim0: new support task for port
> > ModemManager[2490]: <debug> [1621709598.549585] [plugin-manager] task
> > 4,mhi_mbim0: deferred until min wait time elapsed
> >
> > Then we find all these ports in the wwan subsystem:
> >
> > ModemManager[2490]: <debug> [1621709598.566894] [wwan0] port contents loaded:
> > ModemManager[2490]: <debug> [1621709598.567007] [wwan0]   bus: pci
> > ModemManager[2490]: <debug> [1621709598.567104] [wwan0]   device:
> > /sys/devices/pci0000:00/0000:00:1b.0/0000:01:00.0
> > ModemManager[2490]: <debug> [1621709598.567195] [wwan0]   driver:
> > mhi-pci-generic
> > ModemManager[2490]: <debug> [1621709598.567285] [wwan0]   vendor: 1eac
> > ModemManager[2490]: <debug> [1621709598.567390] [wwan0]   product: 1001
> > ModemManager[2490]: <debug> [1621709598.567488] [base-manager] adding
> > port wwan0 at sysfs path:
> > /sys/devices/pci0000:00/0000:00:1b.0/0000:01:00.0/mhi0/wwan/wwan0
> > ModemManager[2490]: <debug> [1621709598.568261] [filter] (wwan/wwan0)
> > port allowed: wwan device
> > ModemManager[2490]: <debug> [1621709598.568542] [base-manager]
> > additional port wwan0 in device
> > /sys/devices/pci0000:00/0000:00:1b.0/0000:01:00.0
> > ModemManager[2490]: <debug> [1621709598.568823] [plugin-manager] task
> > 4: port grabbed: wwan0
> > ModemManager[2490]: <debug> [1621709598.568968] [plugin-manager] task
> > 4,wwan0: new support task for port
> > ModemManager[2490]: <debug> [1621709598.569059] [plugin-manager] task
> > 4,wwan0: deferred until min wait time elapsed
> >
> > What is this "wwan0" port exposed by the wwan subsystem? It doesn't
> > have a protocol reported, still, it's exposed in the system.
>
> Oh, I see now that it's not a port (wwan_port), it's the actual device
> (wwan_dev)
>
> $ sudo udevadm info -p
> /sys/devices/pci0000:00/0000:00:1c.0/0000:08:00.0/mhi0/wwan/wwan0
> P: /devices/pci0000:00/0000:00:1c.0/0000:08:00.0/mhi0/wwan/wwan0
> L: 0
> E: DEVPATH=/devices/pci0000:00/0000:00:1c.0/0000:08:00.0/mhi0/wwan/wwan0
> E: DEVTYPE=wwan_dev
> E: SUBSYSTEM=wwan
> E: USEC_INITIALIZED=41894749
> E: ID_MM_CANDIDATE=1
>
> $ sudo udevadm info -p
> /sys/devices/pci0000:00/0000:00:1c.0/0000:08:00.0/mhi0/wwan/wwan0/wwan0p2MBIM
> P: /devices/pci0000:00/0000:00:1c.0/0000:08:00.0/mhi0/wwan/wwan0/wwan0p2MBIM
> N: wwan0p2MBIM
> L: 0
> E: DEVPATH=/devices/pci0000:00/0000:00:1c.0/0000:08:00.0/mhi0/wwan/wwan0/wwan0p2MBIM
> E: DEVNAME=/dev/wwan0p2MBIM
> E: DEVTYPE=wwan_port
> E: MAJOR=510
> E: MINOR=1
> E: SUBSYSTEM=wwan
> E: USEC_INITIALIZED=41895254
> E: ID_MM_CANDIDATE=1
> E: ID_MM_PORT_TYPE_MBIM=1
>
> > Due to
> > this, we attempt to probe with all known protocols we may have in the
> > subsystem:
> >
> > ModemManager[2490]: <debug> [1621709600.082522] [plugin/generic]
> > probes required for port wwan0: 'at, qcdm, qmi, mbim'
> >
>
> Nah, this port probing is just something we log, we can then not do
> any kind of probing because this is not a /dev port.
>
> What we need to do is ignore all events if DEVTYPE=wwan_dev as we
> don't require them for anything. Loic what do you think? we should
> probably update the candidate udev tag only to match
> DEVTYPE==wwan_port, right?

Absolutely, there is nothing to do with the wwan_dev for now, so it
can be ignored.

Regads,
Loic